Advice on minisplit placement
I’m in the process of replacing baseboard resistance heat with mini splits, and could use some advice on placement. The house is wood frame, 2 x 6 wall, R-19 fiberglass and some R-23 rock wool in areas that have been redone, with 3″ of Comfortboard rock wool being added to exterior as siding is replaced. Roof eaves overhang 32″, so good shading. Outdoor 99% design temperature is 13 degrees; 1% is 89. Indoor design heating is 70 degrees, cooling is 75 degrees.
Climate zone 4A, 45 miles north west of Philadelphia.
The upper floor has sloped roof up to an 8′ level, insulated to R-45, with R-60 insulation above flat section in middle 8′ of rooms. A Manual J calculation (based on exterior being covered with Comfortboard sheathing) shows upper floor heat loss of 5179 btu, heat gain of 7220. First floor heat loss is 11,185, heat gain is 7220 btu.
First floor is over basement that is well-sealed at perimeter; walls are Superior precast, with foam insulation. I’m not sure of R-value – they currently advertise R-21, but the house is 24 years old and I doubt whether it is that well-insulated. Foam appears to be about 1 1/2 inches thick. There is R-19 fiberglass between floor joists supporting first floor.
I’ve attached rough plans of lower and upper floors. An HVAC contractor I’ve worked with has suggested a floor mount Fujitsu 9RLFFH unit at “x” position at right end of upper level and a floor mount Fujitsu 12RLFFH unit at “x” position at left end of lower level. We’d prefer floor units, for appearance reasons and to avoid problems that might result from mounting wall units too close to ceiling. Both bathrooms will probably have small baseboard resistance units.
Does this look like a workable plan? Are there better locations/sizing options for the indoor heads? Would it be worthwhile to increase size of first floor unit to 15RLFFH? Compressors for both will be located at rear of house, so line sets and drains will run to basement and out back.
Thanks for any advice.